Cosmetic preparations are available nowadays to the consumer in a large number of combinations. In this regard, it is not only expected that these cosmetics exhibit a particular care effect or overcome a certain deficiency, but there is an evermore frequent requirement for products which have several properties at the same time and thus exhibit an improved performance spectrum. Of particular interest are substances which both favorably influence the technical properties of the cosmetic product, such as storage stability, photostability and ability to be formulated, and also at the same time constitute active ingredients which confer care, irritation-suppressing and/or photoprotective properties for skin and/or hair for example. Especially, good skin compatibility and particularly good skin compatibility for humans with sensitive skin is of increasing importance.
Sensitive skin is a condition of subjective cutaneous hyperactivity to environmental factors or stimuli. Approximately 40% of the population considers themselves to possess the characteristics of sensitive skin. Consumers who perceive their skin as sensitive report exaggerated reactions when their skin is in contact with cosmetics, soaps and sunscreens, and worsening after exposure to dry, cold or wind climate, to sun or UV irradiation, to polluted environment, to physical treatments as depilation, shaving, or to stress. They react with subjective symptoms like itching, burning, stinging, prickling or tingling.
Mechanistic aspects of sensitive skin are still unclear, but an increased permeability of the stratum corneum and acceleration of the nerve response in skin are considered to be involved.
Various literature papers address the cosmetic treatment of sensitive skin. In Parfums Cosmetiques Actualités, 2004, 178, 128-169, C. Chavigny reviewed the different strategy and products to increase the skin tolerance threshold, via restoration of the cutaneous barrier and via limiting the production of the cellular mediators involved in the inflammatory reaction.
The peptides endomorphin-1 (H-Tyr-Pro-Trp-Phe-NH2) (SEQ ID NO:5) and endomorphin-2 (H-Tyr-Pro-Phe-Phe-NH2) (SEQ ID NO:6) are known pharmaceutical agents.
WO 98/42732 (EP 0 994 897) discloses the peptides endomorphine-1 (H-Tyr-Pro-Trp-Phe-NH2) (SEQ ID NO:5) and endomorphine-2 (H-Tyr-Pro-Phe-Phe-NH2) (SEQ ID NO:6) and several structural variations and their use in pharmaceutical compositions. No cosmetic use is described. No synthetic variants (acetylated forms) are disclosed.
WO 03/020304 (EP1427438} describes pharmaceutical compositions comprising an endomorphin for use in the treatment or prophylaxis of inflammation as well as autoimmune disorders such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, psoriasis or asthma. The endomorphin is selected from natural endomorphins, synthetic endomorphins, endomorphin analogues, endomorphin mimetics, functional fragments of natural endomorphins, functional fragments of synthetic endomorphins and endomorphin derivatives. In a preferred embodiment, endomorphin-1 or endomorphin-2 are used. The endomorphin derivatives described are such that are obtained by glycosylation, sulphation or hydroxylation or “any other known modification method for peptides.” The peptide derivatives of the present invention are not disclosed nor their cosmetic use.
WO 97/07130 (EP 845003 B1) describes tetra-peptides and tetra-peptide derivatives and their pharmaceutical use in the treatment of pain. The tetra-peptide always contains either D-Ala or D-Arg. WO 95122557 discloses oligopeptides, among them endomorphine-2 and their pharmaceutical use in the treatment of pain. U.S. Pat. No. 4,350,627 discloses a variety of tetra and penta-peptides and their therapeutic use.
The object of the present invention was to provide cosmetic compositions which are suitably to be used by humans with sensitive skin. In a further object of the invention, the cosmetic compositions should not only prevent subjective symptoms of sensitive skin like itching, burning, stinging, prickling or tingling but should also ameliorate existing symptoms of sensitive skin. It was a further objective of the invention to provide cosmetic compositions which help relieve sensitive skin in decreasing subjective cutaneous hyperactivity to environmental factors or stimuli and attenuating corresponding skin subjective symptoms like itching, burning, stinging, prickling or tingling. It was a further objective of the invention to provide cosmetic preparations which allow the incorporation of known irritating agents such as e.g. alpha-hydroxyl acids or retinol, in cosmetic preparations with the goal to obtain non-irritating compositions, which can thus be safely applied by humans with sensitive skin.
In addition, the cosmetic formulations should be preferably non-toxic and compatible with the most common cosmetic ingredients.
Surprisingly, it has now been found that oligopeptides according to the invention satisfy the needs described above.
None of the documents of the prior art describe oligopeptides of the invention nor the cosmetic use of the claimed oligopeptides. None of the documents describes oligopeptides which can be used on sensitive skin.